From the reports Tom's has posted, it looks like the Titan will out-perform the 7970, pretty much across the board (even the Toxic version).
Still (as you know) the HD7970 is a VERY strong GPU. The next generation of Radeon offering looks to be very promising as well.
Idk I read that review too, and the 7970GHz fell within 20-30% many times. I feel it would be very doable.
Problem is, all of the benchmarks TH ran are with programs I really can't reproduce. However I may check out other websites...